Depends on Communities. In Newton you would like to have the T within walking distance but not close enough to see it or hear it.
In Needham we have the commuter rail again, nice to be able to walk to it, but not have it in your back yard.
Brookline, its everywhere except in the South Brookline.
All these communties are not effected only by having the T, but all are very accessable by car and most families have 2 -4 cars depending on age of kids.